Swimming in a pool—especially on hot summer days—sipping wine or soda, and opting for a cup of tea vs. coffee to kick your day off right might all be awesome ideas, but they all have the capacity to stain your teeth. Really? Yes. Really.

With Memorial Day coming around the corner, we suggest keeping your mouth closed when taking a swim in the pool. "I see this mostly in avid swimmers, but pool water can create spots on your teeth called swimmers calculus," says Beverly Hills-based cosmetic dentist Kevin B. Sands, DDS, who tends to the teeth of a ton of celebrities, including former Cosmo cover girls Miley Cyrus and Kim Kardashian. "What happens is the high pH of the chemicals in the pool water causes the proteins in your teeth to harden into a dark brown tartar. And to remove the stains, professional whitening is required." No bueno.

Another surprising way you can wreak havoc on your pearly whites without knowing it: We all know that dark-colored sodas and red wine can stain your teeth, but clear soda and white wine can also do some damage. "Lighter colored beverages are acidic and chromagen-rich and can cause significant staining," says Sands. "The acidity softens the tooth enamel and then sets the stage for further staining."

Lastly, if prefer tea over coffee, don't think you're exempt from staining. "Black tea, for example, is rich in stain-promoting tannins that can cause worse staining than coffee. Try sipping these drinks [and the ones above] through a straw to minimize the amount of liquid that's actually coming into contact with your teeth," advises Sands.

For more ways to score whiter teeth (and keep them that way), click here.